This invention relates to an X-ray diffraction apparatus which radiates a thin bundle of X-rays to a material and detects the diffracted X-rays from the material.
If a thin bundle of X-rays is radiated only to a microsmall region of a material (such as a spot of about 100 .mu.m, for example), the number of radiated crystal grains and the number of diffracted X-rays from the material can be reduced (to 3 to 5, for example) and hence, the diffracted X-ray for each crystal grain can be detected. The use of such a micro-beam of X-rays leads to the advantage that the crystal structure as well as the degree of strain between the crystal grains can be detected. However, it is difficult to arrange in advance an X-ray detector at a position where it is capable of detecting the diffracted X-rays, because the number of diffracted X-rays is small and their directions are different.
To solve the abovementioned problems, there has conventionally been proposed an apparatus in which a large, semi-circular X-ray detector of the belt-like form is disposed around the radiating position of a small material in such a manner as to cover the anticipated range of angle of the diffracted X-rays (Japanese Patent Laid-Open No. 60843/1980). However, this apparatus is not free from the problem in that the apparatus becomes complicated in construction and large in size and can only be adapted to a small material.